Telephone number

Telephone numbers are something we all are used to. Today most people have multiple telephone numbers: office, mobile, and home. The office and home numbers are associated with specific connections to the telephone companycentral office, whereas the mobile number is associated with a specific telephone. The format of the number in North America is dictated by the North American Numbering Plan (NANP): (area code)-exchange code-subscriber code. The area code and the exchange code are often referred to as NXX, where N can be any digit from 2-9 and X can be 0-9. The NANP is administered by Neustar.